The present invention relates to a thermal insulating window for curtain walls in which the heat insulation characteristics thereof are not lowered as a whole.
The heat insulation capacity of a curtain wall has a considerable effect on the efficiency of air conditioning. In effect, in some building structures where the room has a window, the ability of the walls to ensure thermal insulation for the room is largely dependent on the structure of the window. Consequently, high demand has been placed on the development of an effective thermal insulating window of a design or structure that enables the window to be constructed into the wall of the room without diminishing the heat insulation capacity of the wall as well as the room as a whole.
German Patent Public Disclosure No. 2855022 is the closest prior art to the present invention. FIG. 3 is a horizontal cross sectional view of the heat insulating window for a curtain wall in accordance with the above German Patent Public Disclosure No. 2855022. The heat insulating window "a" adiabatically mounted to a column member "a" of the building generally comprises a thermal insulating window "b", thermal insulating window framework "c" inserted and fixed to the vertical member "a" and a window body "d" mounted to the thermal insulating window framework capable of opening and closing. The thermal insulating window framework "c" comprises an internal framework member "e" secured to the room side member of the vertical member of the building and external framework member "g" connected to the internal framework member "e" by means of a pair of thermal insulating members "f", "f". On the other hand, the thermal insulating window body "d" comprises an internal window casing "h" mounted to the internal framework member and capable of opening and closing, and an external window casing connected to the internal window casing through a pair of thermal insulating members "i", "i". A sealing member "k" is provided between the insulating thermal window framework "c" and the window body "d" so that a thermal insulating space is defined therebetween.
Therefore, in the conventional thermal insulating window, thermal insulation at the thermal insulating window itself and the space between the thermal insulating window framework "c" and window body "d" is efficiently carried out through one or more of the thermal insulating members or thermal insulating space. However, this conventional thermal insulating window has some disadvantage in that thermal insulation of the window body itself, particularly at the junction of the glass and window casing is not sufficient. Thus, in the conventional thermal insulating window a large quantity of heat can be transferred through the window casing because the outside portion of the internal window casing is in contact with a batten "l" which is open to outdoor air. This construction leads to poor thermal insulation at this point. Further, the external window casing in the conventional thermal insulating window connected to the internal window casing through the paired of the thermal insulating members "i", "i" does not function sufficiently as a thermal insulating member so that the total cost for manufacturing the thermal insulating window is increased in proportion to the increased members.